The estuarine portion of the Mill River in Fairfield, CT, consists of two water body segments. Segment CT-W1_005 is located from the mouth of Southport Harbor (parallel to Willow Street) upstream to Harbor Road in Fairfield. Segment CT-W1_006 begins at the Harbor Road crossing on the Mill River and continues upstream to the Sturges Road crossing of the river.

{study area} Within these segments, the Mill River is classified as a Class SA surface water body. In accordance with the Connecticut Water Quality Standards, as a Class SA water body, the Mill River should support a healthy aquatic and wildlife community, support recreational activities and be a resource for fishing and shellfishing. However, data for the water body indicates that these uses are not currently attained. For this reason, the estuarine portion of the river has been identified as impaired for aquatic life uses, recreation and shellfishing.

Section 303(d) of the federal Clean Water Act requires states to develop a Total Maximum Daily Load Analyses or an equivalent plan to identify the cause and sources of the impairments, set environmental goals to resolve the impairments, and implement the necessary changes. The causes of the impairments have been identified as bacteria, lead, and chromium. Information is provided below for each of these pollutants to identify the necessary pollutant reductions needed, and activities in support of those reductions.

Bacteria

One cause of the shellfishing impairment within the Southport Harbor is elevated concentrations of bacteria. A Total Maximum Daily Load analyses has been established by CT DEEP, and approved by EPA, to identify potential sources of bacteria to the water body, and set pollution load reductions necessary to restore sanitary quality, within the water body, such that shellfishing uses could be restored. The TMDL for this portion of the Mill River is part of the Statewide Bacteria TMDL and is specifically addressed within the Appendix for Estuary 4: Westport-Fairfield.

The lead contamination within the Mill River was evaluated as part of human and ecological risk assessments conducted by the Exide Group Incorporated, as required by CT DEEP. Risk assessments have shown that lead in the sediments is impacting the recreational use of the river due to risks from direct contact with sediments containing lead, as well as accumulation into fish and shellfish tissues, which could pose a risk to people who might eat the fish and shellfish.

In response to the contamination, a fish consumption advisory has been established recommending that people not eat Blue Crab from the Mill River estuary. The risk assessments also demonstrated that the aquatic life and avian communities were at risk, due to exposure to lead.

The Exide Group Incorporated is under order to remediate the lead contamination associated with the former Exide Battery Manufacturing facility which was located on the banks of the Mill River. The upland portion of the cleanup has occurred and the company is preparing to conduct remedial activities to address the sediment contamination.